lubberger



F LUBBERGER TELEPHONE EXCHANGE TRUNKING SYSTEM.

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I 6 7 O I 4 0 oO 1 WFA/55555 F. LUBBERGER.

TELEPHONE EXCHANGE TRUNKING SYSTEM.

APPLlcmoN FILED MAY s. 1910. nemzwin Dsc. 6. ma.

1,904,0'26. Patented May 20, 1919.

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F. LUBBERGEH.

TELEPHONE EXCHANGE TRUNKING SYSTEM. l APPLlcATloN man MAY e. 1910. nznzwso Dsc. 6. Isla.

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F'. LUBBERGER. TELEPHONE EXCHANGE TRUNKING SYSTEM.

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1,304,076.' Patented May 20, 19192 5 sums-sum 4.v

' 'F.LUBBERGER.

TELEPHONE EXCHANGE TRUNKING SYSTEM. APPLICATION FILED MAY`611910. RENWED DEC. 6.1918.

5 SHEETS-SHEET 5- lHlllllllllllla WTA/55555 Patented May 20, 1919.

UNITED sTATEs PATENT oEEIcE FRITZ LUBBERGEB, 0F CHICAGO, ILLINOIS, AASSIGNOR TO AUTOMATIC ELECTRIC COMPANY, 0F CHICAGO, ILLINOIS, CORPORATION 0F ILLINOIS.

TELEPHONE-EXCHANGE TRUNKING SYSTEM.

Specification of Letters Patent.

Application mea nay s, 1910. serial ne. 559,821. Renewed Deeember s, 191s. seriai Ne. 265,645.

To all `wlw/1L it muy concern:

Be it known that I, Fm'rz LUBBERGER, a subject of the Emperor of Germany, and resident of Chicago, Cook county, Illinois, have invented a certain new and useful Improvement in Telephone-Exchange Trunking Systems, vof which the following is a specification. l

My invention relates to telephone systems of that kind in which main and branch exchanges are employed. Systems of this kind have been used` in which automatic switches were provided for establishing connection between a subscribers line of the branch exchange and a subscribers line of the main exchange, or between lines located at different branch exchanges. It has also been possible in s vstemsof this kind for thesubscribers of the branch exchange to intercommunicate without using the apparatus at the main exchange. For such purpose soca-lled rotary connectors have been employed at the branch exchange, which connectors were made rotary on the tenth level and were thereby capable of selecting idle 'trunks leading to the `main exchange, vthe other levels being used for making local calls. lVith this arrangement, however, the branch exchange would involve only ninety subscribers lines, the entire tenth level of each connector being employed for automatic trnnkin to the main exchange, and no 'selectora ing employed between the subscribers lines and the said connectors.

The principal object of my invention is, therefore, to provide a system of this character in which ordinary or standard connectors can `be employed at the branch exchange, and inwhich only one Contact of each connector bank will be used for trunk.

lines terminating at different branch ex-v changes, as will hereinafter more fully appear.

With my improved arrangement, therefore,

the capacity of the branch exchange is not only materially increased, but the construction of the connectors fis also simplified, it being posslble to use ordinary or standard connectors in place of the so-called rotaryconnectors heretofore employed for this purpose.

To the foregoing and other useful ends my invention consists in matters hereinafter set forth and claimed. l In the accompanying Idrawings Figure l 1s a diagrammatic lay-out of an automatic telephone system embodying the principles of my invention.

Figs. 2, 3, 4e and 5 taken together show diagrammatically a complete circuit connection established between a calling branch exchange substation A and a main exchange substation A in the system shown in Fig. 1.

The branch exchange shown at X in Fig. l comprises the substations A to which there are allotted the line switches C. The connectors shown at E are accessible from the line switches C, and in turn have access to the subst-ations in the branch exchange. The connectors E also control means by' which the line switches C may obtain connection with the main exchange through a secondary line switch F, there being one of these switches for'every connector. These Patented May 20, 1919.r

line switch C, secondary switch F, repeater H.7 thence overtrunk conductors to the .main exchange, through a first selector I, second selector J, connector l( to the subst-ation A. It will also be seen that it is possible for substation A to call substation A through the medium of the line switches C', first selectors I, second selectors J line switches C, connectors E, and thence to the substation A. Of course, the main exchange X may comprise a number of groups of substations A together with their accompanying line, selector and connector switches.

The trunks leading from the secondary switches F at th-e branch exchange terminate in first selector switches I at the main exchange, just as do the trunk lines leading from the main exchange subscribers line switches C. These trunk lines are used only for calls from the branch to the main exchange. For calling 'fromthe main exchange t0 the branch exchange a set of trunks is provided leading from the banks of the second selectorsJ in the main exchange to line switches C in the branch exchange, which line switches are just likeithe branch exchange subscribers line switches and, like them, have access to the connectors E. Thus, after obtaining connection with one of these trunks, the main exchange subscriber may call any subscriber in the branch exchange, just as the subscriber at substation A would call them.

In Fig. 2 there is shown diagrammatically a substation A, line switch C, master switch D and connector switch E.

Fig. 3 is a similar view of a secondary lin switch F controlled by the master switch D',

" 'which is `similar to the master switch D by the substations in the branch exchange to the automatic switches in the main exchange.

Fig. 4 is a similar view of a first selector switch I and second selector J. At K (Fig. 5) there is shown a similar view of a connector. Fig. 5 also shows a substation A and a line switch C' which are similar to the substation A and line switch C shown in. Fig. 2. In the various drawings, a number of ringin current generators R and R are shown, W ile at M, M and M2 busy signaling machines are represented. J As shown, each exchange is provided with a battery B having one terminal grounded, preferably its positive terminal.

Fig. 6 is a diagrammatic representation of the essential features of the master switch D (Fig. 2). i

The automatic substations may be of any suitable or approved type. As herein represented, the substation A comprises the usual receiver 2, switch hook 3, transmitter 4, bells 5, condenser 6, impulse wheel 7, and impulse springs 8 and 9 which are. made to break contact upon the backward rotation of the impulse wheel 7. The switch hook 3 has a cam arm 17 attached to it which causes the springs 11 and 12 to be engaged as long as the receiver is on the hook, but as soon the substatious to operate the central otiice bank of springs which forni the terminals ofY trunk conductors leading to connectors E,

\and causesthe springs 22, 23, 24 and 25 to.

ehgage the springs 26, 27, 28 and 29, respectively. Although there is only one se't of bank springs (22-29) shown, there may, hdWever,-be a plurality of such sets in each bank to which the plungers ot' the several line switches C have access. The magnet 18 of the line switch C comprises four windings, namely, a pull-in winding 30, a cut-oil' winding 31, auxiliary winding 32 and line winding 33. The magnetic circuit of the windings 30 and 31 is separate from'that oi the windings 32 and 33, due to the center of the core ofthe magnet being mounted upon the bracket 18a. The winding 30, when energized, serves to pull up both armature 20 and the plunger arm 19, while the winding 31 will only pull up the armature 20 from an unoperated position, but will hold the plunger a-rm 19 in an operated position after it has once been pulled up by the vWinding 30. The operation 'of the magnet 18 will be more fully explained later.

The master switch D is of the general type disclosed in the aforesaidvBritish patent and also in the American Telephone Joe/.111ml of June 6, 1908. It'controls the plungers of the group of line switches of which the switch C is a member in such a manner that they are normally held in front of an idle trunk line leading to a connector E. It consists essentially of the motor 1nagnet 34 and the master switch bank a which comprises the individual segments and the common segment 36. The wiper 37 serves to hold one of these individual segments in electrical connection with the common segment 36. The switch D also has a 'number of operating relays, one of which 4controls the locking plate 39. The ratchet wheel 38 is operated by the armature 40 of the motor magnet 34.

The trunk conductors leading from the line switch banks to the connector pass through the springs of relay 41, the purpose of which will be more fully explained later.

The connector shown at E is of the general ty e disclosed in U. S. Letters Patent #815,1 6, granted March 13, 1906, to Keith, Erickson and Erickson. Among other details it comprises a shaft (not shown) carrying wipers 42, 43, and 44, which have a vertical movement controlled by the vertical magnet 45 and a rotary movement controlled by the rotary magnet 46. rll`he slow relay 47 controls the private magnet 48,

which in turn controls the. side. switch which carries the wipers 49, 5o, .'31, .'32 and 521. The. relays 4-7 and 54 are slow acting-that. is, they are slow to dcincrgize after their circuits are broken. The operation of the switch is controlled through the medium of the double-wouiid line relay 55. flhe release of the connector switch is brought about by means of the release magnet 57.

'llhe first selector l shown in Fie'. -1 is of the general type disclosed in UJS. lietters Patent #8155321, granted March 18, 19013, to Keith, ltlrickson and llrickson, being modified slightly to operate in conjunction With a two-wire system. lt comprises the private magnet 1J.- which controls the side switch, carrying wipers' 122, 1211, 124 and 125, in the usual and well-known manner. 1t also comprises the slow-acting relays 1212, 139 and 147, vertical magnet 141), rotary magnet 1413, douhle-wound relay 121, release magnet 216 and a shaft carrying the wipers 141, 142 and 143. rlhe mechanism of the selector is restored to normal position inin'iet'liately upon the energization of its i,'e lease magnet, rather than by its dciinergiZation. as shown in said selector patent.

The selector .l is similar to the selector l.

As indicated in Fig. 1, the branch exchange isy provided with a number of connectors ll. 'lhe corresponding contacts in the banks of all these connectors are multipled together and connected with the respective subscribers lines. ln order to provide means for calling a subscriber in the main exchange, l find it advisable to leave some particular set of contacts in each connector bank disconnected from the corresponding contacts in the other banks.

'fn Fig. 2 is represented a p ortion of one level in the banks of two connector switches showing this disconnected contact. llach bank level, of course, consists of two sets of line contacts and o and u, and (1.', respectively, and one set of private bank contacts and (1F, respectively. The first set of contactsof thislevel is shown as being reserved for the purpose of calling the uiain ex- `change. The line contacts of this set have no connections at all. rPhe. first contact 92 of the private bank ffl is connected with the relay 41 and with the line switch lf (Fig. 1l). Likewise. the first contact. of the bank u? would be connected to a separate line switch similar to the switch F, and to the relay ,41. belonging to the ti'uiik line leading to its own connector.

For convenience of explanation it is assumed that thecontact which is reserved for calling the main, exchange is the first contact in the 'tenth or 0 level. Thus any subscriber at the branch exchange may obtain a trunk line leading to the main exchange by operating his calling mechanism for the digits 0 and 1. After obtaining connection with the l assumed to be 222() in the niain exchange.

11s has been explained, the subscriber at slibstation A must pretix the digits 0 and 1 to the number 2220.

'l'he first operation on the part of the calling subscriberis to remove the receiver 2 from the hook 3, which permits the hook to rise, thereby opening the circuit. of the bells at springs 11 and 12, and bridging the receiver, transmitter and impulse springs inl series across the line conductors 15 and 1G by pei'inittirng the Aengagement of' springs 12 and 115. lhc closing ot this bridge across the line conductors 15 and 16 closes an enerv rizing circuit through the winding 33 of the magnet 18 of line switch (l. '1`his circuit exteiids from ground fl through springs 59 and (30, conductor 16, springs 12 and 13, impulse springst and 9, receiver 2, transmitter 4, conductor 15, springs 61 and (i2, winding 33 to battery lead 63, thence through battery ll to grolmd G. The line winding 33, upon energizing, attracts the armature 21, which forces spring 58 into engagement with spi'iiig 59. This closes a circuit extending from ground ti through springs 5 9 and 58, winding 3() and winding 32 to battery lead ($3, thencel through battery vl to ground r1`he energizing of winding 30 pulls up the armature 2() and plunger arm 19. The `pulling up of armature 20 breaks the circuit, of line winding 325. armatui'c 21 does not fall back immediately, however, but is held up for a moment by the current fiowing through the winding 32, which is short-eircuited at the springs 19*i and 20 when the arm 19 operates, and therefore deinergizes slowly. Simultaneous with the attriuftion of the armature 2() is the attraction of the plunger arm 19. As before stated, the arm 19, in its operated position, closes the. liies to vthe connector ll through the springs of the relay +1. 11s soon as the lines are closed to the connector E a circuit is close-d extending from ground (i2 through lower winding of relay 55, springs G4 and ($5 of relay 41, bank springs 29 and 25, conductor 16, springs 12 and 13 of substation A. iiiipillse springs 8 and 9, receiver 2, transmitter 4, conductor 15, bank springs 22 and 26, springs (5G and 67 ot' relay 11,

The.

upper` winding of relay 55 to. battery lead (33. The relay 55, upon energizing, closes an energizing circuit through the slow relay 54. This circuit extends from ground G3 through springs` ($8 and (39 and relay 54 to battery. The, relay 54, upon energizing, opens the release magnet circuit at springs 71 and 7'4.

The closing of springs 73 and 74 put-s the vertical magnet in readiness to receive impulses by the grounding of spring 70. The engagement. of springs 75 and 76 closes a circuit through the cut-otf winding 31 of Aline switch "C This circuit extends from ground G4 through side switch wiper 49, springs 7 5 and 7 G, bank springs 27 and 23 to the point 7 7, thence through winding 3l to battery. A branch, also leads from the point 77 over normal conductor 78 to the private bank contact of the calling line in the banks of all of the connectors that have access to the calling line, thus preventing another party from calling substation A while it is making a call. The circuit through the winding 3l is closed before the armature 21 falls back, thereby keeping the lplunger arm 19 and armature Q0 in an attracted position. As soon as the bank springs 24 and 28 are brought into engagement by the plunge-r` a circuit is closed extending from ground G5 through springs 24 and 28 to the contact 35 of the master switchbank, thence. through wiper 37, common segment 36 and relay 79 to battery. The relay 79, upon energizing, closes the circuit offrelay 80, which relay in turn closes a circuit through the motor magnet 34, lifts the pin 81 out of engagement with the locking plate 39 and puts a busy signal onto the lilies of the idle line switches of the group controlled by the master switch D. This busy signal reaches the line from the machine M by means of the induction between windings 32 y and 33. .The locking plate 39 is secure-ly fastened to the shaft which controls the plunger ot' line, switch C, and the pin 81 engages an opening in the said locking plate only when the plungers stand directly in front of a trunk leading to one of the connectors E. and as long as the pin 81 is in engagement with an opening in said locking plate, the shaft is held against rotation.

The circuit closed through the motor mag net by the energization of relay 80 extends from ground G through motor magnet 34, interrupter springs 84, contact 82, armature 83 to battery. The motor magnet pulls up to break its own circuit at springs 84*1 and to rotate the ratchet wheel 38 one step.

'By a suitable mechanical device the' rotary motion of the ratchet wheel is imparted to the plunger shaft, giving said plunger shaft an oscillatory motion to move the plungers in register therewith back and forth in front of the trunk terminals. As the shaft is thus rotated, the hole in the the magnet energizes and denergizcs in the Y manner of a buzzer to move the plungers to the next trunk, at which point the pinv 81 will again engage an opening in the plate 39.- If the next trunk should happen to be busy, the wiper 37 will find the contact next to the one last put in use grounded, and the relay 80 will be energized as before and hence the plungers will be carried to the next idle trunk. As before stated, the busy signaling machine M supplies the busy signal to any subscriber that attempts to call while the masten switch is operating.

The foregoing is the operation of the apparatus at the private branch exchange upon the removal of the receiver at substation A./ The apparatus is now in readiness for the operation of the dial for the first digit by the subscriber at substation A. As the dial is now operated in the usual manner Jfor the first digit, which in this case is 0, the line at the substation is broken ten times by the separation oit the impulse springs 8 and 9 by the impulse teeth 10. `This opening of the line 'at substation A breaks the circuit of the double-wound line relay 55 of the connector E. The momentary denergization of the relay 55 closes the circuit of the vertical magnets ten times to raise the shaft and lshaft wipers ten steps to a point opposite the tenth level of contacts in the connector banks. The circuit through the vertical magnet extends from ground G3 through springs 68 and 70, 74 and 73, (the relay 54, being slow acting, does not denergize during the momentary interruptions or' its circuit), verticalmagnet 45, side switch wiper 50, relay 47 to battery. The relay 47 energizes in series with the, vertical magnet upon the first impulse and, being slow acting, does not denergize until yafter the last impulse has been delivered. In its energized position the relay 47 closes a circuit through the private magnet 48. This circuit extends from ground-G7 through springs 84 and 85, private magnet 48 to battery. The private magnet denergizes, upon the denergization of the relay 47, and permits the side switch to pass to second position. The side switch wiper 50 (in second position) connects the lrotary magnet 4G to battery through the wiper 50, relay 47 to battery. The rotary magnet encrgizes once to rotate the shaft and. shaft wipers one step onto the bank conttu'its of the trunk leading tothe second; ary switch 1". The relay 47 energizes and fleiinergizes, as before, to close the circuit of the private. magnet, which permits the side switch to pass t0 third position upon vdeenergizing.

'1`he sideI switch wipers 52 and 53 (in third position) have no function at this time, as it will be. remembertal that the two line trunks have been disconnected from the contact upon which the connector now stands. ln passing to the third position the wiper 40 shifts the holding ground for the cut-off winding 31 of the line switch (l from ground (il4 to ground tlf, r1`he passing of the wiper 50 to the third position closes an energizing circuit through the ringer relay 88, but this also is functionless at this time. The wiper 51 (in third position) closes a circuit through the relay 41 in nulltiple with the winding 85) of the secondary switch l". The. circuit through the relay 41 extends from ground (1N through the wiper 5,1, springs 90 and 91, shaft wiper 43, private. bank contact 92, conductor 03 and relay 11 to battery. The, relay 41, upon energizing, disconnects the trunk conductors 04 and 05 from the connector VE at the springs 04 and 05, and 00 and 07, and connects said conductors dileetly to the `bank springs 100 and 110 of the switch lf,- over the conductors 102 and 1023, by causing the engagement of the springs (30 and 00, and (35 and 97. The circuit through the winding H0 of the, magnet 100 extends over thel same circuit. as traced for the relay 41 to the private contact 02, thence over the conductor 101, through the winding 85) to battery. The, magnetlf,

upon energizing, attracts the plunger arm 104. which acts in the. same manner as the. plungil arm 10 of the lineI switch (l to force, the )lunger into the. bank of trunk terniinais leading to a repeater 1l. 'lhe actuation of the plunger arm "104 also inserts the winding 105 in circuit in series with the winding 89 by shifting the spring' 100 out of engagement with the spring 107 and into engagement with tin-spring 10.8. '1`he engagement of the springs l0!) and 110 with the springs 111 and 112, respectively closes an energizing circuit. through the double wound line relay 113 of the repeatei ll. This circuit extends from ground (1 through the lower winding of said relay, springs 112 and 110, conductor 103, springs 07 and (35, 29 and 25, thence. to and through substation A back over the line 15, springs 22 and 20, 00 and 00, conductor 102, springs 10S) and 111 ,and the upper winding of the relay 113 to battery. rl`he relay 113 energizes over this circuit and closes a circuit through the slow relay 114 extending from ground (11" through the s )rings 115 and 116, relay/.114 to battery. 'l`1e relay 114, upon eiu-.i-gizlng, supplies a new holding ground for the windings 8S) and 105. '1`his ground extends kfrom ground ti" through the springs 117 andv 118, bank springs 119 and 120, through the two windings of the magnety 100 in series, and thence to battery.. A ln'anc,h also extends to the conductor 101. '1`he object of this ground on the conductor 101 is to supply a holding circuit for the relay 41, the release of the connector having made this necessary, `as will now be explained. lt will be remembered that upon the energization of the relay'41, the circuit of the double line relay was broken, th'us allowing it to detnergize and brcakthe circuit of the relay 54. After a short time the relay 54 deiinergizes and closes the circuit of the release magnet 57. This circuit extends from ground (1 through the springs 08 and 70, 74 and 71, release magnet 57 and. springs 110n and 120l to battery. The release magnet energizes to release the switch innnediately. As the shaft returns to norlnal position itl disengages the springs 111i:l and 120, thus breaking the-circuit. of the release nlagnet. Since the relay 54 is slow act ing` this release of the connector does not take place until the line switch l and connector ll have had time to operate to extend ground back over the conductor 101, as in the manner explained. r1`he line switch C is held in an operated position over a eircuit extending from the conductor 101 (which is grounded, as before described), through the springs 0S) and 08, 27 and 2211 and winding 31 of the line switch to battery. Asshown in the drawings, the springs of the relay 41 are make before break in order that the talking circuit may be cut through to the repeater to energize the line l'elay 113 thereof before the lille. relay of the connector falls back. r1`his is necessary in order that ground may be sent back from the repeater to the conductor 101 before 'the ground is removed therefrom at the connector. Springs 08 and 00 of the rela\v 4l are adjusted to make before the rest of the springs to connect the holding circuit from the, repeater with that. of the line switch before said circuit is broken at the connector.

'lhe double-wound line. relay 113,'when energized, closes a circuit through the double-wound line relay 121 of the selector I. 'l`his circuit extends from ground (11 through thel lower winding of the relay 121. side switch wiper conductor 120` illipedance coil 12T, springs 128 and 120, conductor 1210side switch wiper 123 and upper winding of the relay 121 to battery lead 131. The relay 121 operates to close the. circuit of the slow relay 132. This circuitv extends from ground (im through the springs 133 i and 134 and relay 132 to battery; The relay 132 energizes and opens the release mag'- net circuit at the springs 135 and 13G.

The master switch 1) 4operates the same as the master switch D to move the plun-s gers to the nexit idle trunk.

1t is evident from the foregoing that, at'tcr the subscriber at substation A has called U1, a connection is completed through the repeater H to a selector I in the main exchange. The connector E, which was used in establishing said connection, is restored to normal position. The switches are now in position to receive the impulses for the third digit 2. As the circuitot the double-wound relay 113 of the repeater is broken twice in response to the subscriber-s calling device, it denergizes and breaks the circuit of the relay 121. The circuit of the relay 114 of the repeater is also broken, but the relay 114, being slow-acting, does not denergize during this momentary interruption of its energizing circuit.

` 121 deenergizes twice in response to the breaking of its circuit at the repeater, and closes the circuit of the vertical magnet 140 twice. This circuit extends from ground G13 through the springs 133 and 137, 135 and 138, relay 139, magnet 140 and side switch wiper 124 to the battery lead 131. The vertical magnet energizes twice to raise the shaft and shaft wipers 141, 142 and 143 two steps to a point'opposite the second level of bank contacts. The relay 139 in the circuit with the vertical magnet is slowacting, and therefore acts in the same manner as the relay 47 of the connector E to hold closed a circuit through the private magnet 144 until the last impulse has been delivered to the vertical magnet. The private magnet then denergizes and permits the side switch to pass to second position. The side switch wiper 124 (in second position) closes a circuit extending from ground Gil2 through interrupter springs 145, rotary magnet 146, slow relay 14'( and-side switch wiper 124 to battery. The rotary magnet 146 energizes over this circuit to rotate the shaft and shaft wipers one step onto the bank contact of a trunk leading to a second selector switch J, push down private inagnet armature, and to break its own circuit at springs 145. If the first contact upon which the shaft wipers are rotated is idle, the rotary armature falls back, because its circuit is broken at springs 145, and releases the private magnet armature, which in turn allows the side switchto pass to the third position. Should the first trunk be busy, however, the private wiper 142 will find a guarding ground potential upon the first contact, in a manner hereinafter more fully explained. A circuit is now comv pleted extending from the ground potential The relay on the private bank contact through the private wiper 142, side switcli.wiper 125 (in second position), privateymagnct 144 to battery, thereby holding the n'ivate magnet in an energized position, wlhich locks the side switch in second position. The rotary magnet again energizes immediately upon its deiinergization and rotates the shaft wipers another step, as before. llt' this seoond trunk is busy, the operation will be repeated to rotate the shat't wipers to the first idle trunk leading to a selector J, whereupon the private magnet dcnorgizes and permits the side switch to. pass to third position. rlhe wipei's 122 and 123, upon passing to third position, closea circuit through the doublewound line relay 148. This circuit extends from ground (im through lower winding of relay 148, side switch wiper 149, shaft wiper 143, side switch wiper 122 thence over the heavy conductor to and through impedance coil 127 of" repeater H, springs 128 and 129, conductor 130, wipers 123, 141 and 150, upper winding of relay 148. to battery. The relay 148 energizes and closes the circuit of the slow relay 154 in the same manner as the circuit of relay 132 of selector I was closed. The relay 154 energizes, and in addition to performing the functions that were performed by relay 132, it extends a guarding ground potential back over conductorf155 to the private bank contact of the selector J in the banks of all ot' the first selectors that have access to the selector J. This ground extends from ground Gr15 through side switch wiper 152. springs 156 and 157 and conductor 155 to the said private bank contacts. The relay 147 of the selector I being slow acting remains energized for a moment after the side switch has passed to third position. Thus it supplies ground to the private bank contact above referred to between the time that the side switch passes to third position and the time that the ground potential is put back by relay 154 of the second selector. The relay 147 supplies this guarding potential over a circuit extending from ground G1" through springs 158 and 159 to private wiper 142. This guarding ground is to prevent another switch from stopping on the trunk leading to selector J before relay 154 of selector J operates. The relay 147 is quicker than the relay 132, however, and denergizes in time to close a holding circuit for relay 132 before it has time to deenergize after its circuit is broken by the deenergization of relay 121. The holding circuit of relay 132 extends from ground G1 to wiper 142, as 'before traced, thence through side switch wiper ,125 and springs 159 and 159*a to and through'relay 132 to battery lead 131. y

The selector J operates in the saine man- 50 contacts.

` 160, upon energizing. closes a circuit through the slow relay 1161, which in turn 'energizes and puts a holding ground 'back to the. release relays ot' selectors l and J to hold them in an energized position. Upon the l5 operation of the. dial for the fifth digit. 2,

the repeater operates as before described to break the circuit of relay 160. '.ll`he relay 16() thereupon deiinergizes twice and. closes the circuit. ot' the vertical magnet 168, which 20 operates to raise the-shaft and wipers 164-,

165 and 166 two steps. The private magnet relay 167 cnergizes and closes the circuit. of the privatemagnet 168. A moment-'after the line is open t'or the last time., the private magnet is allowed to deenergize, which permits the side switch to passto second position. 'l`l1e subscriber now operates the dial t'or the last digit t). The impulses, instead ol being sent to the vertical magnet,

are transferred to the rotary magnet, which energizes to rotate the shaft and shaft wipers ten steps onto the line of the. called subscriber. It' this line is idle, the side switch is permitted to pass to the third 85 position in the usual manner. rl`hus t'ar the operation has been similar tothe operation ot' the connector E, before described. When the wipers 169 and 17() pass to the third position'. the conductors 174 and 175 are 40 completed to the line of the called subscribcr through the condensers 176 and 177.

1n passing to third position .the wiper 171 puts a guard-ing ground onto the private bank contact of the"called line in thc banks o'l'iall ot' the connectors that have access to 'the called line. This circuit' extends from ground (11 through thc wiper 171, springs 219 and 22() of the busy locking relay 221, private wiper 165 to the said private bank A circuit also extends Jfrom this ground at' the private, \\"iper-165 over the minductor 222 through the winding 223 ot the line' switch (1 and thence to battery.l

rl`he armature 22-1 is attracted upon the closure ot' this circuit and operates to bring the spring 19() into engagement with thc spring 189, which closes the linc to the called substation. The operation ot' the armature 221 also disconnects the linc windl0 ing 225 Jr'roni the. called line. rlhis prevents lthrough thc bells 188 over a circuit. cxtending,r from one side ot' the generator It through tbc. springs 187 and 183, wiper 179, shat't wiper 164, springs 189 and 19t), conductor 191, bells and condenser 188, springs 192 and 192), conductor 194-` wipers 166 and 169, ringer relay springs 182 and 186 to the opposite side. ofthe generator lt. 'l`he subscriber at'. substation A', upon hearing the signal, removes the receiver t'rom the hook. This operation allows the spring 198 to discngage the spring 192 andto engage spring 195. -l'Vhen this occurs, or as soon thereafter as the ringer relay 178 is deiinergizer by the interruptcr 179, a circuit is closed through the double-wound bat-.kridge relay 196 ot' the connector K. 'This circuit extends from ground (11 through wiper 171, lower winding otl relay 196, springs 182 and 184, wipers 169 and 166, conductor 194, springs 198 and 195, impulse springs 197, receiver 198, transmitter 199, conductor 191, sp1-.ings 19() and 18-9, wipers 164 and 170, springs 183 and 185, upper winding ot relay 196 to battery. Talking current for the called su'hstation is also`t'urnislied over the circuit just traced. The. relay 196, upon energizing, breaks the circuit ot the ringer relay u178. The springs 26() andl 201 also engage, but without results at' thistime. A conversation may now be carried on between the two subscribers at subst ations A and A without interruption.

'lhe release of the apparatus used in establishing this eo-nnection is initiated by the calling subscriber in replacing` the receiver on the hook. It will be remembered that the relay 118 of the. repeater is energized during the conversation over a circuit `extending through the springs 12 and 12) ot substation A. '.I`herefore, when the receiver at substation A is placed on the hook the springs 12 and l'tdisengagc and break the circuit of relay 112). When the relay 118 deiinergizes it breaks the circuit ot the. relays 114 and 16() (Fig. 5). rlhe relay 111-, upon deiinergizing, breaks the circuit ot' the windings 89 and 105 ot' the switch F, and also breaks position. As the 4relay 160 dcnergizes it breaks the holding circuit of the relays 161, l54'and 132 of the switches K, J and I, re. speetively. The relay 161, upon energizing, operates to close a circuit through the release n'lagnet 202. The circuit throughy the magnet 202 extends from gro-und G1 through the springs 203 and 204, springs 205 and 206, magnet'202, spring 208 and contact 207, thence to battery. The opening of the circuit of the relays 154 and 132 allows them to dcnergize and close Ythe circuits of their respective release magnets. The circuit through the release magnet 209 of the selector J extends from ground G20 through the springs 210 and 211, springs 212 and 213', magnet 209, contact 21,14 and spring 215 to battery. The circuit through the release magnet 216 of the selector I extends from ground G13 through the springs 133 and 137, springs 135 and 136, magnet 216, contact 217 and spring218 to battery. The various release magnets, upon energizing, release their respective switches. The shafts of the switches, upon returning to normal position, break the circuits of the release magnets. All of the switches used in the connection are thus restored to normal position and are in readiness foranother call.

f Returning now to that point in the operation of setting up the connection when the connector K passes onto the called line, but before the side switch has passed to the third position: If the called line is busy the private wiper 165 will find a guarding ground on the private bank contact, as has been described. When the relay 167 denergizes after the last impulse of the last digit has been delivered, the guarding ground at the private bank contact provides a locking circuit for the private magnet 168. This cir-l cuit extends through the wiper 165, springs 220 and 219, lower winding of the relay 196, springs 184 and 182, side switch wiper 1619 (in second position), springs 227 and 226 of the relay 167 and private magnet 168 to battery. The side switch thus remains locked in second position and the relay 196 energizes, closing -a circuit extending from ground G21 through the springs 228 and 229, 230 and 231, relay 221 and springs 200 and 201 to battery. The relay 221 energizes to disconnect the rotary magnet from the spring 204 at the springs 232 andy 233. It A, also shifts the holding ground for the relay] 196 and ma et 168 from the private wiper to ground (122 by shifting the spring 219 out of engagement with the spring 220 and into engagement with the spring 234. This prevents the connector side switch from passing to the third position in case the called line becomes idle.

The engagement of the springs 235 and 236 upon thev energizing of the relay 221 puts a busy signal on the line of the calling subscriber. This circuit extends from battery through the sewndary of the induction coil 237, springs 236 and 235, wiper 170, ringer springs ISI-fand 185, condenser 177, thence over the vheavy conductor to and through the substation back over the heavy conductor, through the lower winding of the relay 160 of the,- connector bl to ground. rThe calling subscriber, upon receiving the busy signairep-laces the receiver on the hook, thereby releasing the switches lin a manuel' hereinabove described.

If, now, the subscriber A desires to call another subscriber in his own exchange, the line switch G is operated, upon the removal of the receiver from the hook, in the same manner as before to complete connection to the connector E. rlfhe subscriber at substation A will now call the desired number, which will consist of two digits. The connector E now operates in exactly the same manner as did the connector K, before described, to complete connection to the called line.

The calling subscriber receives his talking battery current from the circuit through the double-wound line relay 55 instead of through the double-wound relay of the repeater, as in the other connection. The release of the switches in this connection is brought about in the same manner as before described. When connection is made with one of the branch exchange substations through the medium of the connector E, the relay 41 is not operated and the talking circuit between the two substations extends from the calling substation over the conductors shown in heavy lines in Fig. 1 to the springs 66 and 65 of the relay. 41, thenee through the spring 67 on one side of the line and the spring 64 on the other side, condensers 238 and 239, normally closed springs of the ringer relay 88, side switch wipers 55 and 52 and shaft wipers 42 and 44 to the bank contacts of the called line.

From the foregoing it will be seen that I provide an improved trunking system in which ordinary or standard connectors are employed for making local calls, and also for extending a trun ring connection to another exchange. I-Ieretofore, as previously explained, rotary connectors have been used for this purpose. Connectors of this kind are not only more or less complicated, as they are required to be automatically rotary in one or more levels thereof, but they also tend to limit the capacity of the branch exchange, because only ninety subscribers lines can be connected with the bank of each connector. In other words, at least one entire level of a rotary connector must be iven over to automatic trunking, thus alowing ninety contacts for subscribers lines.

to a. non-numerical trunking switch. This4 trunking switch then selects an idle repeater, and through the medium of the repeater the calling su scriber controls the two sides of the telephone line in series to successively operate the first and second selectors and the connector at the main exchange, if the call is to a. linelterminating at the latter. If the call is from one branch exchange to another, then the repeater is used for controlling the selectors at the main exchange, and for then controlling a connector at the branch ex- `change. When the connector at the branch exchange 1s employed for establishinfra connection with the main exchange, it oes not vremain in operation, as it is released upon the establishment of such `connection. It is, however, at such time not available for use by other subscribers, as the trunk to which it is allotted is made busy and remains so until after the subscribers are through using it for conversing. In other words, the non-numerical trunkin switch that selects the idle repeater is su stituted for the connector in the establishment of the connection with the main exchange.

What I claim as my invention is l. In a telephone system, a branch exchange provided with automatic connectors, subscribers lines terminating in the banks of said connectors, a main exchange, and means including a particular contactv of each connector bank for effecting a trunking connection from the branch exchange to the main exchange, which particular contacts are excluded from the trunking connections between the two exchanges.

2. In a telephone system, a branch exchange, a main exchange, lconnectors at the branch exchange, subscribers lines terminating in the banks of said connectors, means at the branch exchange for automatically selecting idleconnectors, means for effecting a trunklng connection from the branch exchange to the main exchange by a particular operation of any one of sard'connectors, and means for automatically releasing the connector Without breaking the established trunking connection between the two exchanges. i

3. In 'a' telephone system, a branch ex,-

change, `a main exchange, connectors at the branch exchange, subscribers lines terminating in the banks of said connectors, means at the branch exchange for automatically selecting idle connectors, non-numerical trunking switches at the branch exchange for use inetrunking therefrom to the main exchange, means whereby a particular operation of any connector serves to operate one of said nonnumerical trunking switches, and means for automatically releasing the operated connector without disturbing the connection established by the non-numerical trunking switch. f

4. In a tele hone system, a trunk line, a relay for esta lishing connection therewith, a connector, telephone lines terminatingin the bank of said connector, means whereby a particular operation of said connector serves to energize said rela and means whereby the energizing of sai relay restores the connector to normal position.

5. In a tele hone system, a trunk line, a relay control ing connection therewith, 'a connector, telephone lines terminating in the bank of said connector, an energizing circuit for said relay controlled at a certain point in the connector bank, whereby a particular operation of. said connector serves to establish a connection with said trunk line and to release said connector, and a talking circuit including said trunk, the circuit of said relay being excluded from the talking circuit.

6. In a telephone system, an automatic connector, means for using said connector in eifecting a calling connection, means for automatically restoring said connector to normal osition after operation thereof, without isturbing the calling connection, means ,for releasing the calling connection, andv means preventing further use of said connector until after said connection is released.

7. In a telephone system, a branch exchange provided with automatic connectors, subscribers lines terminating in the banks `of said connectors, a main exchange, means including a articular contact of each connector bank /or effecting a trunking connection from thebranch exchange to the main exchange, which particular contacts are excluded from the trucking connections between the two exchanges, and means for controllin said connectors over two sides of the cal ing line in series.

8. In a telephone system, a branch exchange, a main exchange, connectors at the branch exchange, subscribers lines terminating in the banks of said connectors, means at the branch exchange for automatically selecting idle connectors, means for eiecting a trunking connection Jfrom the branch exchange to the main exchange by a particular operation of any one of said connectors, means for automatically releasing the conalsY nector .without breaking the established trunking connection between the two exchanges, and means for controllinw said connectors over two sides of the calling line in series.

9. In a telephone system, a branch exchange, a main exchange, connectors at the branch exchange, subscribers lines terminating in the banks of said connectors, means at the branch exchange for automatically selecting idle connectors, non-numerical trunking switches at the branch exchange for use in trunking therefrom to the main exchange, means whereby a particular operation of any connector serves to operate one of said nonnumerical trunking switches, means for automaticall releasing the operated connector without isturbing the connection established by the non-numerical trunking switch, and means for controlling said connectors yover two sides of the calling line in series.

10. In a telephone system, a trunk line, a relay for establishing connection therewith, a connector, telephone lines terminating in the bank of said connector, means where 'y a particular operation of said connector serves to energize said relay, means whereby the energizing of said relay restores the connector to normal position, and means for controlling said connector over two sides of the calling line in series.

11. In a telephone system, a trunk line, a relay controlling connection therewith,- a connector, telephone lines terminating in the bank of said connector, an energizing circuit for said relay controlled at a certain point in the connector bank, whereby a particular operation of said connector serves to estab- Vlish a connection with said trunk, a talking circuit including said trunk, the circuit of said relay being excluded from the talking circuit, and means for controlling said connector over two sides of the calling line in series.

12. In a telephone system, an automatic connector, means for using said connector in effecting a calling connection, means for automatically restoring said connector to normal osition after operation thereof without disturbing the calling connection, means for releasing the calling connection, means preventing further use of said connector until after said connection is released, and

means for controlling said connector over two sides of the calling line in series.

13. In a telephone system, a branch exchange provided with automatic connectors, each connector being provided with a bank consisting of roups of contacts, subscribers lines terminating in all but one of said contacts, a main' exchange, and means including the remainingr contact of each connector bank for effecting a trunking connection from the branch exchange to the main exchange, said connectors having first subscribers lines terminating in the banks of said connectors, a main exchange, and means including a particular contact of each connector bank for etfectino' a trunking connection from the branch exc ange to the main exchange, which particular contacts are excluded from the trunking connections between the two exchanges, said connectors having first one motion to select a group and then another motion to nd a called line in the predetermined group, both of said motions bein controllable over the two sides of the calling line in series.

15. In a telephone system, a branch exchange, a main exchange, connectors at the brauch exchange, subscribers lines terminating in the banks of said connectors, means at the branch exchange for automatically selecting idle connectors, means tor etl'ectin a trunking connection from the branch exc iange to the main exchange by a particular operation of any one of said connectors, and means for automatically releasin the connector without breaking the established trunking. connection between the two exchanges, said connectors having Iirst one motion to select a group and then another motion to find a called line in the predetermined group, both of said motions being controllable over the two sides ot the calling line in series.

16. In a telephone system, a branch exchange, a main exchange, connectors at the branch exchange, subscribers lines terminating in the banks of said connectors, means at the branch exchange for automatically selecting idle connectors, nonnumerical trunking switches at the branch exchange for use in trunking therefrom to the main exchange, means whereby a particular operation of any connector serves to operate one of said non-numerical trunking switches, and means 'for automatically releasing the operated connector without disturbing the connection established by the non-numerical trunking switch, said connectors having first one motion to select a group and then another motion to find a called line in the predetermined group, both of Said motions being controllable over the two side of the calling line in series.

17. In a telephone system, a trunk line, a relay for establishing connection therewith, a connector, telephone lines terminatanother motion to find a called ing in the bank of said connector, means whereby a particular operation of said connector serves to energize said relay, and means whereby the energizing of said relay restores the connector to normal position, said connector having first one motion to select a group and then another motion to find a called line in the redetermined roup, both of said motions in controlablel over the two sides of the ca ling line in series.4

`18. In a telephone system, a trunk line, a

i relay vcontrolling' connection therewith, a

connector, telephone lines terminating in the bank of said connector, an energizing cir-v cuit for said relay controlled at a certain point in the connector bank, whereby a particular operation of said connector serves to establish a connection with said trunk, and a talkingcircuit-includingsaid trunk, the circuit of said relay being excluded from the talking circuit, said connector having rst one lmotion to select a groupand then ine in (the predetermined group, both of said motions being controllable over the two sides of the callin linein series. I

19. n'atelephone system, an automatic connector, means for using said `connector in effecting a'calling connection, means for automatically restoring said connector to normal position after o eration thereof Without disturbing the ca ling connection, means for releasing the calling connection, and means preventing 'further use of said connector until after said connection is released, sagid connector having first one motion to se ect a group and then another motion to nd a called line in the predetermined group, both of said motions being controllable over the two sides of the calling line in series.

20. In a telephone system, Va branch ex- 'change provided with automatic connectors, each connector being provided with a bank consisting of groups of contacts, subscribers lines terminating in all but one of said contacts, a main exchange, means including the remaining contact of each connector bank for effecting a trunking connection from the branch exchange to the main exchange, a central source of talking and operatin current, and means whereby theA current or operating urposes is controlled over the two sides oI the calling line in series, an automatic progressively movable switch at the main exchange, and means for operatingl said switch over said trunking' connection.

21. In a telephone system', a branch exchange provided with automatic connectors, subscribers lines terminating in the banks of said connectors, a main exchange, means including a articular contact of each connector bank or effecting a trun-king connec- I tion from the branch exchange to the main exchange, which particular contacts are excluded from. the trunking connections be tweenthe two exchanges, a central source of talkin and operatin current, and means whereby the current tor operating purposes is controlled over the two sides of the calling line in series.

22. In a telephone system, a branch exchange, a main exchange, connectors at the branch exchange, subscrlbcrs lines terminating in the banks of said connectors, means at the branch exchange for automatically selecting idle connectors, means for effecting a trunking connection vfrom the branch exchange to the main exchange by aparticular operation of any one of said connectors, means for automatically releasing the connector without breaklng the established trunking connection between the two `vcxchanges, a central lsource of talking and ope'rating current, and means whereby the current for operating purposes is vcontrolled over the two sides of the calling lin'e in series.

23. In a telephone system, a branch exchange, a main exchange, connectors at the branch exchange, subscribers lines terminating in the banks of said connectors, means at the branch exchange `for automatically selecting idle connectors, non-numerical trunking switches at the branch exchange for use in trunking therefrom to the main exchange, means whereby a' particular operation of Vany connector serves to operate one ofsaid non-numerical trunking switches, means for automatically releasing the operated connector without disturbing the connection established by the non-numerical trunking switch, a central source of talking and oper- -ating current, and means lwhereby the current for operating purposes is controlled over the two sides of the calling line in series.

24. In a telephone system, a: trunk line, 'a relay for establishing connection therewith, -a connector telephone lines terminating in the bank or2 said connector, means whereby a particular operation of said connector serves to energize said relay, means whereby the energizing of said relay restores the connector to normal position, a; central source of talkin r and operating current, and means where y the current for operating purposes is controlled over the two sides ofthe calling` line in series.

25. In a telephone system, a trunk line, a relay controllin connection therewith, a connector, tele one lines termin-ating in the bank of sald connector, an energizing circuit for said relay controlled at a certain point in the connector bank, whereby' a particular operation of said connector Serves to establish a connection with said trunk, a talking circuit including said trunk,

the circuit of said relay being excluded from the talking circuit,a central `source of talking and operating cui-rent, and inca-ns whereby the current for operating purposes is controlled over the two sides ot' the calling line in series.

26. In a telephone system, .an automatic connector, means for using said connector in effecting a calling connection, means for automatically restoring said connector to norinal position after operation thereof wit-hout disturbing the calling connection, means for releasing the calling connection, means preventing further use of said connector until after said connection is released, a central source of talking and operatin current, and means whereby the current or operating purposes is controlled over the two sides of the calling line in series.

27. In a telephone system, a branch exchange provided with automatic connectors, each connector being provided with a bank consisting of ten parallel rows of contacts of ten contacts each, subscribers lines termi-l nating in ninety-nine of said contacts, a main exchange, means including the remaining contact of each connector bank for effecting a trunking connection from the branch exchange to the main exchange, numerical switches at said main exchange, and repeaters controllable over any subscribers line to control said numerical switches.

28. In a tele hone system, a branch exchange provid with automatic connectors, subscribers lines terminating in the banks of said connectors, a main exchange, means including a particular contact of each connector bank for effecting a trunking connection from the branch exchange to the main exchange, which particular contacts are excluded from the trunking connections between tlie two exchanges, numerical switches at said ma'in exchan e, and repeaters controllable over any su ribers line to control said numerical switches.

29. In a telephone system, a branch exchange, a main exchange, connectors at the branch exchange, subscribers lines terminating in the banks of said connectors, means at the branch exchange for automatically selecting idle connectors, means for effecting a trunking connection from the branch exchange tothe main exchange by a particular operation of any one of said connectors, means for automatically releasing the connector without breaking the established trunking connection between the two ex-v changes, numerical switches at said main exchange, and repeaters controllable over any subscribers line to control said numerical switches.

30. In a telephone system, a branch exchange, a main exchange, connectors at the branch exchange, subscribers lines terminatng in the banks of said connectors,

means at the branch exchange for automatically selecting idle connectors, non-numerical trunking switches at the branch exchange for use in trunking therefrom to the main exchange, means whereby a particular operation of any connector serves to operate one of said non-numerical ti'unking switches, means for automatically releasing the operated connector without disturbing the connection established by the non-numerical trunking switch, numerical switches at said main exchange, and repeaters controllable over any subscribers line to control said numerical switches.

31. In a tele hone system, a trunk line, a relay for estab ishing connection therewith, a connector, telephone lines terminating in the bank of said connector, means whereby a particular operation of 'saidI connector serves to energize said relay, numerical switches at the other end of said trunk line, and repeaters controllable over any sub- -scribers line to control said numerical switches.

32. In a telephone system, a trunk line, a relay for establishing connection therewith, a connector, telephone lines terminating in the bank of said connector, means whereby a particular operationl of said connector serves to energize said relay, means whereby the energizing of said relay restores the connector to normal osition, numerical switches at the other en of said trunk line, and repeaters controllable over any subscribers line to control said numerical switches.

83. In la telephone system, a trunk line, a relay controllin connection therewith, a connector, telep one lines terminatin in the bank of said connector, an energizing circuit for said relay controlled at a certain point in the connector bank, whereby a particular operation of said connector serves to establish a connection with said trunk, a talking circuit including said trunk, the circuit of said relay being excluded from the talking circuit, numerical switches -at the other end of said trunk line, and re eaters controllable over any subscribers ine to control said numerical switches.

34. In a telephone system, an automatic connector, means for using said connector in effecting a calling connection, means for automatically restoring said connector to Anormal position after operation thereof without disturbing the calling connection, means for releasing the calling connection, means preventing further use of said connector until after said connection is released, numerical switches, and repeaters controllable over any subscribers line to control said numerical switches for use in establishing said calling connection.

35. In a telephone system, a trunk line, an automatic switch having a plurality of bank asesor@ automatic switch having a plurality of .bank

contacts and a movable wiper, a relay connected'in circuit with one of said contacts and adapted to be energized when said wiper connects with said contact,'means controlled by said relay for extending a connection to said trunk line, and means whereby the energizin of said relay 4 restores said automatic switc 1 to normal position.

37. In a telephone system, a trunk line, an automatic switch havlng a plurality of line contacts and a bank of pivate contacts, a prlvate wiper, a relay connected 1n clrcult with one of said private contacts and adapted to be `energized when said private wlper connects with said private contact, and means controlled by said relay for extending a connection to said trunk line and for releasing said automatic switch without destroying the connection to said trunk line. l

38. In a telephone system, a .trunk line,an automatic switch having a plurality of'line contacts and a bank of private contacts,"a`

private wiper, a relay connected in circuit with one of said private contacts and adapted to be energized when said private wiper connects with said private contact, means controlled by said relay for extending a connection to said trunk line, and means whereby the energizing ot said relay restores said automatic switch to normal position.

39. In a telephone system, a trunk line, an automatic switch having a plurality of bank .contacts and a movable wiper, a relay connected in circuit with one of said contacts and adapted to be energized when said wiper connects with said Contact, means controlled by said relay for extending a connection to said trunk line and for eliminating the said automatic switch from the established connection, and means for controlling said automatic switch over two sides of a line circuit in series.

40. In a telephone system, a trunk line, an automatic switch having a plurality of bank contacts and a movable wiper, a relay connected in circuit with one of said contacts and adapted to be energized when said wiper connects with said contact, means controlled by said relay for extending a connection to said trunk line, means whereby the energizing of said relay restores said automatic switch to normal position, and means for controlling said automatic switch over two sides of a line circuit in series.

41. In a telephone system, a trunk line, an automatic switch having a plurality of line contacts and a bank of private contacts, a

private wiper, a relay connected in circuit wlth one of sald private contacts and adapted to be energized when said private lwiper connects with said private contact, means controlled 'by said relay for extending a connection to said trunk lineand for releasing the said switch without interfering with the trunk line connection, and means for controlling said automatic switch over two sides ofga line circuit in series. i l 42. In a telephone system, a trunk line, a automatic switch havmg a plurality of line contacts and a bank of private contacts, a private wiper, a relay Aconnected in circuit with one of said private contacts and adapted to be energized when/said private wiper connects with said private contact, means controlled by said relay forextending a connection to said trunk line, means whereby the energizing of said relay restores said auto- !matic switch to normal position, and means foricontrolling said automatic switch over two sides of a line circuit'in series.

43. In a telephone system, calling lines, a progressively movable connector switch, means for connecting any one of said lines with said switch, a plurality of other lines having terminals in said connector switch, means whereby said connector may be operated to establish aconnection from the calling line to any one of said other lines, a relay, means for applying a potential to a terminal of. one ofsaid other lines for energizing said relay to extend a connection from a calling line to said other line and to disconnect said switch from the extended connection, and means for supplying current for talking purposes to some of said lines from a central source.

44. In a telephone system, calling lines, a progressively movable-connector switch, means for, connecting any one of said lines with said switch, a plurality of other lines having terminals in said connector switch, means whereby said connector may be operated t-o establish a connection from the calling line to any one of said other lines, a relay, means for applying a potential to a terminal of vone of said other lines for energizing said relay to extend a connection from a calling line to said other line and to release the said connector switch, an automatic switch on said other line, and means for theri transmitting impulses from the` calling-line over said other other line to opi a relay` means for applying a potential to a terminal of one of said other lines fOr energizing said relay to extend a connection from a. calling line to said other line and to eliminate the. connector switch from the connection without interfering with the said connection, and means for controlling Said connector switch over two sides of the calling line in series.

Jft. In a. telephone system, calling lines, a progressively movable connector switch, means for connecting any one of said lines with said switch, a plurality of other lines having terminals in said connectorswitch, means whereby said connector may be operated to establish a connection from the calling line to any one of said other lines, a relay, a means for applying a potential to a. terminal of one of said other lines for energizing said relay to extend a connection from a calling line to said other line and for releasing the connector switch from the extended connection, said vwnnector switch having two motions, one to select a group of said other lilies, and another to locate an individual line in the selected group.

li'. In a telephone s vstem. a trunk line, a relay controlling connection therewith, a talking circuit including said trunk line, a connector, telephone lines terminating in thel bank ot' said connector. an energizing circuit for said relay controlled at a Certain point in the connector bank` whereby a particular operation ot' said connector serves to establish a connection with said trunk line and to eliminate the connector from the talking circuit, the circuit of said relay being excluded from the talking circuit.

' 48. In a telephonel system, a trunk line, a. relay controlling connection therewith, a talking circuit including said trunk line, a cmmector, telephone lines terminating in the bank of said connector, an energizing circuit for said relay controlled at a certain point in the connector bank, whereby a particular operation of said connector serves to establish a connection with said trunk line and to eliminate the connector from the talking circuit, the circuit of said relay being excluded from the talking circuit, and means for supplying current for talking purposes to said lines from a central source. 49. In a telephone system, a trunk line, an automatic switch having a plurality of bank contacts and a movab e wiper, a relay and means controlled thereby, said relay connected in circuit with one of said contacts and adapted to be energized when said wiper connects with said contact to extend a connection through the medium of said means to said trunk line andv to release the said automatic switch without destroying the connection, and means for supplying current for talking purposes to said lines from a central source.

50. In a telephone system, a trunk line, an automatic switch having al plurality of bank contacts, a movable wiper, a relay connected in circuit with one of said contacts and adapted to be energized when said wiper connects with said contact, and means controlled by said relay for extending a connection to said trunk line and for eliminating the said automatic switch from the connection. v n

51. In a telephone system, a trunk line, an automatic switch having a plurality of line contacts and a bank of private contacts, a private wiper a relay connected in circuit with one of said private contacts and adapted to be energized when said private wiper connects with said private contact, and means controlled b said relay for extending a connection to sai trunk line and for eliminating said automatic switch from the extended connection.

52. In a telephone system, calling lines, a progressively movable connector switch, means for connecting any one of said lines with said switch, a plurality of other lines having terminals in said connector switch, means whereby said switch may be operated to establish a talking circuit from a calling line to any one of said other lines, a relay, means for ap lying a potential to a terminal of one of Said) other lines for energizing said relay to extend a connection from a calling line to said other line and to release the said connector switch, an automatic switch on said other line, and means for transmitting impulses from the calling line over two sides of the talking circuit in series to operate said automatic switch.

53. In a telephone system, calling lines, a progressively movable connector switch, means for connecting any one ot' said lines with said switch, a plurality of other lines having terminals in said connector switch, means whereby said switch may be operated to establish a talking circuit from a calling line to any one of said other lines, a relay, means for a plying a potential to a terminal of one o said other lines for energizing said relay to extend a connection from a calling line to said other line and to release the said connector switch, an automatic switch on said other line, and means for transmitting impulses over two sides of the talking circuit in series to operate said switches.

54. In a telephone system, subscribers lines, means for performing a series of successive selecting operations to establish a connection between two of said lines, a trunk terminal, a trunk normally connected thereto, a second trunk normally disconnected therefrom` means for first performing certain of said selecting operations over said terminal and the normally connected trunk, means for disconnecting said normally confnectcd trunk and connecting said normally disconnected trunk when said selecting operations have reached a certain point, and means for then completing said selecting op crations over said last-mentioned trunk.

In a telephone system, subscribers lines divided into groups, means for establishiiig a connection between two of said lines, said means including a trunk having a single terminal adapted to be seized by a calling subscriber and a air of branches extending from said trun one branch normally connected thereto and extending toward certain of said subscribers lines and the other branch extending toward other of said lilies, and means for irs't extending the call over said normally connected branch and completing t-he connection over said other branch if it is desired to establish a connection with a subscriber reached by said last-mentioned branch, and means for disconnecting said norlnally connected branch during talking.

56. In a telephone system, a trunk line having a single terminal at one end thereof and a pair of branches, one normally connected with said terminal and the other normally disconnected therefrom, a switching relay for controlling said connections, a contact maker, step-by-step means for controlling the operation of said contact maker, and bank contacts with which said contact maker is adapted toengage, certain of 'said contacts being operatively connected with said switching relay, whereby when said contact maker is operated to engage with said connected contacts said switching relay is energized to shift the connection of said trunk terminal to the normally,disconnected branch.

' 5T. In a telephone system, trunk lines having a single terminal at one end thereof and a pair of branches, one normally connccted with said terminal and the other normally disconnected therefrom, a switching mechanism in said trunk, line and pilot wipers controlled by said mechanism, bank contacts with which said wipers are adapted to engage` a relay operatively connected with certain of the contacts in the bank engaged by said pilot wiper, means for energizing said relay when said pilot wiper comes in contact with said contacts, and means operated by the energization of said relay for shifting the connection of said trunk terminal to the normally disconnected branch of the trunk.

58. In a telephone system, a trunk line having a single terminal at one end thereof and a pair of branches, one normally connected with said terminal and the other normally disconnected therefrom, a switching mechanism in the normally connected branch, said switching mechanism comprising a pair of line wipers and a pilot wiper,

means for moving said wipers in a vertical plane and then rotating the saine, bank contacts with which said wipers engage, certain of the contacts in one level of the bank en gaged by said pilot wiper being operatively connected with a relay, means forl closing a circuit through said relay when said pilot Wiper is stepped up to a, proper level and then rotated the proper degree in order to engage said contacts, and means controlled by the energization of said relay to shift the connection of said trunk terminal to the normally disconnected branch.

59. In. a telephone system, a calling line, 4 va lurallty of trunk lines accessible to said ing line, each of said trunk lines having a first .branch and a second lbranch, a switching devlce for shifting a connection from the first branch to the second branch, a trunking switch for said second branch having individual terminals in said switchingdevice, a group of lines for said first branch, a group of lines for said second branch, means whereby said calling line in establishing a connection first extends said connection over said first branch, means for then operating said switching device to shift said connection to said trunkin switch over said individual terminals an said second branch, a

called line, and means including said trunlcl ing switch for completing the connection to said called line over a lme of one of said groups of lines.

60. In a telephone System, a relay, an automatic switch provided Iwith rotary wipers -and means for closing a circuit to energize tion including a trunk individual to saidrelay. 4

62. In a telephone system, a trunk, a switch at one exchange, a switch at another exchange, (branch connections from said trunk to said switches, means for controlling said switches over said trunk, one of said branches being normally open, and a relay controlled over one branch to close said open branch. I

63. In a telephone system, a trunk having a main portion and a plurality of branch portions, means for making local calls over the main portion and one branch portion, and means for making long distance calls over the main portion and another branch portion, one branch beingsufiicient for local calls, and both branches being necessary for establishing a long distance call.

64. In a telephone system, a trunk, a 

